| CDemarest | -- 09-22-2020 @ 4:32 PM |
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This story starts a long time ago. I purchased a 1936 Ford pickup 50 years ago. It was in bad shape. I tore it completely down to the bare frame and have been rebuilding it. About 40 years ago, I bought a rebuilt replacement engine. The one I received had blanking plates on the block where the water pumps were intended to be mounted. I understand that this type block came out in 1937 and it was not a totally uncommon practice to put these blocks into older vehicles as replacements and add the blanking plates. Anyway, around the same time, I bought a rebuilt distributor with the flat top (2 screw) coil. I had the engine running for a very short time back 40 years ago and then the project was put on the back burner until recently. I've been trying to get the engine to run for several weeks with no success. I've purchased and installed a rebuilt distributor body, rotor and points as well as replacing the capacitor and resistor (located on inside of firewall). I purchased a replacement coil (not rebuilt as far as I know). I haven't changed the spark plug wires since the engine was running 40 years ago so I believe they are connected correctly. I know the engine is getting gas because I have a clear plastic tube feeding into the fuel pump and I see the gas being drawn in. The engine cranks but I only get what sound like an single ignition once in a while. The voltage at the input to the coil is 6 volts and then drops down to a little over 3 volts as I crank the starter and I would imagine that the points close. I measure 2,800 ohms over the primary (no condenser) and 8,500 ohms over the secondary coil. Does anyone have any suggestions? Should I look into a rebuilt coil? Many thanks, Charlie Demarest
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| pauls39coupe | -- 09-22-2020 @ 5:25 PM |
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We need a bit more information. If you open the throttle quickly do you get a shot of gas down the carb? Is the gas fresh? Pull one of the spark plugs and crank the engine over with the ignition on. Do you get a fat blue spark from the plug? Run a compression check, do all the cylinders produce at least 75-80 psi?
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| CDemarest | -- 09-22-2020 @ 6:17 PM |
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Thanks. I do know that the gas is fresh. I’ll try your other suggestions.
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| carcrazy | -- 09-22-2020 @ 8:04 PM |
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One way to see if you have any spark at all is to spray some starter fluid into the carburetor before cranking the engine with the ignition switch turned on. If the engine does not even try to fire up and run, you know you have no spark. Does the starter turn the engine over at the normal cranking speed?
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| 40 Coupe | -- 09-23-2020 @ 4:12 AM |
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After sitting for such a long time you may want to do a compression check to see if valves are stuck in open position also.
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| 1931 Flamingo | -- 09-23-2020 @ 6:11 AM |
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Could also be oxidation on the points............... Paul in CT
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| 37RAGTOPMAN | -- 09-23-2020 @ 7:01 AM |
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hi do a compression test, like 40 coupe said, these flatheads had problems when sitting, the valves work stick open, esp for 40 years wow, if the valves are stuck open you can use MMO , to lube them and maybe using a probe push the valves down while turning the motor over, do one cylinder at a time, seems to me if you have one firing ,the rest are stuck open, does it spin over easily ? like no compression ? maybe also using PB BLASTER RUST BUSTER, you should see the valves operating though the spark plug hole, using a strong flash light, If compression is ok it is most likely the spark,, you need three things this to make a engine run, GAS, SPARK, COMPRESSION, all in time, hope this helps, 1937 Ragtopman GOOD LUCK,,, let us hear how you made out,!!! This message was edited by 37RAGTOPMAN on 9-23-20 @ 2:19 PM
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| coup | -- 09-23-2020 @ 7:40 AM |
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Here would be my go at it, remove plugs and re fasten wires, lay plugs so touch engine, plug each hole with cork or twisted paper plug, hit starter with ign on and watch for spark, then go to work on cyl that would not blow out cork or spark. from an old dirt road guy. I do wish you well.
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| TomO | -- 09-23-2020 @ 8:54 AM |
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Your resistance reading for the coil appear to be very high, normal primary is about 1 ohm and secondary is about 4,000 ohms. Tom
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| 40 Coupe | -- 09-24-2020 @ 4:47 AM |
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I suspect you measured coil resistance improperly since the voltage at the coil reacted properly when distributor points were closed.
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| CDemarest | -- 09-27-2020 @ 12:41 PM |
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Thanks to all for the help. I pulled the plugs and with a mini flashlight, I was able to plainly see the valves. All sixteen seemed to open and close fine. I pulled a few plugs and turned the engine over with the ignition on. While grounding the body of each plug to the engine, I didn’t see any spark at all. Previously, I was seeing 6 volts between the coil input and the block that would drop to about 3 volts when I turned the engine over. Something has changed because now the voltage never gets to 6. It bounces between 3 and 3.2 volts as the engine turns. I have two coils and they both exhibit the same thing. Could a set of contacts be stuck closed? Is there someone I could send the whole distributor and coil assembly to for an evaluation? Thanks!
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| carcrazy | -- 09-27-2020 @ 1:02 PM |
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There is a carbon brush in the bottom of the coil that has to contact the rotor in order for spark to be provided to the spark plugs. This brush could be completely worn down or missing from your coil. Take the coil off of the distributor and make sure the brush is in place as well as the spring behind it which causes it to contact the rotor. These brushes and the springs that fit behind them are available separately from some of the V-8 vendors.
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| JayChicago | -- 09-27-2020 @ 1:14 PM |
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No problem with the input voltage to the coil. 3 volts, plus or minus a few tenths of a volt, is what you should see. The ignition resistor reduces the 6 volt battery voltage down to about 3 volt. Previously you saw 6 volt at the coil with engine stopped because at that time the engine just happened to roll to a stop with the points open. While points are open there is no current flow, and therefore no voltage drop thru the resistor. So you saw full battery voltage. If you had bumped the starter to get the points to close, your meter would have then read the 3 volt. This message was edited by JayChicago on 9-27-20 @ 1:22 PM
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| JM | -- 09-28-2020 @ 6:41 AM |
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I would suggest sending your complete distributor to Michael Driskell, at Third Generation Automotive in Tennessee, and let him rebuild it and set the timing on his machine. I would also suggest sending your flattop 2 mounting screw coil to Skip Haney in Punta Gorda, FL to have it rebuilt. Another possibility to check is your ignition resistor mounted on the inside of firewall behind the dash. I have experienced some of these wire wound resistors checking good when cool, but developing high resistance connections (similar to being open) when they are in a heated condition. John This message was edited by JM on 9-28-20 @ 7:21 AM
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| CDemarest | -- 09-29-2020 @ 7:32 AM |
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Thanks, JM. I'm sending them of to those two right now.
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